1. Field of Invention
This invention, as used in the supercharger (the exhaust gas turbocharger) of internal combustion engines or the so forth, relates to the nozzle angle regulator for the adjustable nozzle mechanism of variable capacity turbines and its production method, with regard to the radial flow turbine configured to make the actuating gas flow from the spiral scroll formed in the turbine casing to the turbine rotor in the radial axis through the multiple nozzle vanes having wings of variable angle.
2. Description of the Related Art
In order to make a good match with regard to the internal combustion engine, between the outflow exhaust gas volume from the engine and the actuating gas flow volume which should be determined for the optimum operation condition of the supercharger, variable capacity superchargers, equipped with the variable capacity turbine capable of changing the exhaust gas volume to be sent from the spiral scroll to the turbine rotor in accordance with the operation condition of the engine, have been in widespread use in recent years.
A supercharger with such a variable capacity turbine is equipped with an adjustable nozzle mechanism in order to change the wing angle of the nozzle vane by rotating the nozzle vane with the link assembly so that it is capable of being driven for rotations around the turbine rotor shaft by the actuator through the actuator rod and the driving lever.
For the method to achieve assembling and adjustment of such adjustable nozzle mechanism, an invention of Japanese patent number 3,085,210 has been proposed.
In the concerned invention, a jig should be placed in the inner radius of the nozzle vane to perform the setup for perfect closing of the nozzle vane and the link assembly to be driven for rotations around the turbine rotor shaft. The jig therein can be put in contact with the rear edge of the nozzle vane, wherein the stopper pin is mounted after the nozzle vane and the lever plates are welded together upon putting the nozzle vane in contact with the jig in the state that the stopper pin, that is to be fitted into the long slots located at multiple positions along the circumferential direction of the link plate, is made non-functional or non-existing, and upon fitting the matching pin into the phase matching hole to finalize the entire link assembly in the perfect closing phase.
The position setup for full-opening of the nozzle vane and the link assembly is regulated by the stopper pin making a contact with the edge of the slot provided on the link plate. The opposite edge for the full-opening is facing the edge for regulating the perfect closing.
However, problems, such as the following, are concerned with the invention of Japanese patent number 3,085,210. The setup for the perfect closing and the full-opening positions is regulated by the stopper pin which contacts both edges of the slot. Because of this configuration, if it happens that the pin is cut or broken, or the slot is worn out or cracked down, the nozzle vanes will open more than the allowed maximum angle, and then the rear ends of the nozzle vanes will result in contacting with the turbine wheel 34. If it actually happens, the wheel will be seriously damaged.
In order to avoid such accidents, it is necessary to provide a dedicated spin stopper for the full-opening side, but it makes the configuration more complicated, and increases the number of the assembling parts.
According to the prior arts, the two different processes are required, one of which is to put the jig in contact with the nozzle vane in the nozzle vane-free state wherein the stopper pin to be fitted into the long slots of the link plate is non-functional, and the other process is, keeping the above state, to engage the phase matching hole and the phase matching pin, and set the entire link assembly in the perfect closing phase, then weld the nozzle vane and the lever plate, and fix the stopper pin. This in turn requires more assembling jigs, making the adjustable nozzle mechanism assembly and the related adjustment works troublesome, with additional man-hours resulting in increased costs.
In addition, on the basis of the conventional art in which the structure becomes complex due to the link position determining pin included therein with the stopper pin fitted into the long slot at the multiple positions in the circumferential direction of the link plate, the number of the part category and the number of the parts themselves will therefore increase considerably. As a result, the device costs will increase accordingly.
In consideration of the problems with the conventional art mentioned above, the object of this invention is to propose a variable capacity turbine, requiring neither adjustment process of the full-opening position and the perfect closing position nor the dedicated full position stopper, in which the adjustment works for setting up the full-opening position of the nozzle vanes are not required, and the accidents of damaging the turbine wheel caused by the nozzle vanes which opened excessively can be avoided. It can also simplify the adjustment process for the perfect closing and the full-opening positions, as well as lower the assembly and adjustment costs. The turbine can further simplify the structure for setting the full-opening and the perfect closing positions, and decrease the part category numbers and the number of the parts itself, thus decreasing part costs.
In order to solve the concerned problems, this invention discloses a nozzle angle regulator for adjustable nozzle mechanism, the mechanism comprising; a number of variable nozzle vanes, which are arranged along the circumference of the turbine and provided on the nozzle shafts which are supported on the nozzle mount fixed to the turbine casing in such a way that the nozzle vanes can rotate, and which vary the vane angle; a nozzle driving member having a ring shape for rotating the nozzle shafts of the nozzle vanes, the nozzle driving member being capable of rotating around the turbine shaft by the actuator; and a plurality of joint members of the same number as the nozzle vanes, which connect a plurality of nozzle shafts for nozzle vanes and the nozzle driving member, and which rotate the nozzle shafts with a swing motion forced by the nozzle driving member. This invention specially features that the nozzle angle regulator is provided with two full-opening stopper surfaces provided on at least two neighboring joint members to move the nozzle vanes towards the opening direction and stop the nozzle vanes at the full-opening position by contacting the two neighboring joint members to each other.
For the concrete configuration of the above nozzle angle regulator, a connecting portion of the joint member to couple with the nozzle shaft is provided with a chamfered stopper coupling hole having a flat or curved stopper surface on one sidewall of the stopper coupling hole, a connecting portion of the nozzle shaft to couple with the joint member is provided with a coupling shaft with a stopper surface which is corresponding to the shape of the stopper surface of the coupling hole, the coupling hole of the joint member, and the nozzle vanes and coupling shaft are engaged with each other so that the engagement creates a function to stop the relative rotation by contacting the stopper surfaces of the coupling hole and the coupling shaft setting a predetermined relationship between the engagement angle of the coupling hole and the coupling shaft; and the full-opening stopper surfaces are defined by the angle between the full-opening stopper surface and the engagement line of coupling, the coupling hole and coupling shaft when the nozzle vane is positioned at the full-opening, and the distance between the full-opening stopper surface and the shaft center of the nozzle shaft when the nozzle vane is positioned at the full-opening.
Furthermore, the nozzle angle regulator is provided with a closing stopper surface provided on the joint member and the nozzle mount respectively, the closing stopper surfaces contact each other at the minimum opening angle position of the nozzle vanes, in which the nozzle vanes stop at the minimum opening angle position.
For the concrete configuration of the above nozzle angle regulator, a connecting portion of the joint member to couple with the nozzle shaft is provided with a chamfered stopper coupling hole having a flat or curved stopper surface on one sidewall of the stopper coupling hole, a connecting portion of the nozzle shaft to couple with the joint member is provided with a coupling shaft with a stopper surface which is corresponding to the shape of the stopper surface of the coupling hole, the coupling hole of the joint member, and the nozzle vanes and coupling shaft are engaged with each other so that the engagement creates a function to stop the relative rotation by contacting the stopper surfaces of the coupling hole and the coupling shaft setting a predetermined relationship between the engagement angle of the coupling hole and the coupling shaft; and the closing stopper surfaces are defined by the angle between the closing stopper surface and the engagement line of coupling the coupling hole and coupling shaft when the nozzle vane is positioned at the perfect closing, and the distance between the perfect closing stopper surface and the shaft center of the nozzle shaft when the nozzle vane is positioned at the perfect closing.
The production method of an adjustable nozzle mechanism according to this invention, comprises the steps of: providing a connecting portion of the joint member to couple with the nozzle shaft with a chamfered stopper coupling hole having a flat or curved stopper surface on one sidewall of the stopper coupling hole; providing a connecting portion of the nozzle shaft to couple with the joint member with a coupling shaft with a stopper surface which is corresponding to the shape of the stopper surface of the coupling hole; engaging the coupling hole of the joint member, and the nozzle vanes and coupling shaft to each other so that the engagement creates a function to stop the relative rotation by contacting the stopper surfaces of the coupling hole and the coupling shaft setting a predetermined relationship between the engagement angle of the coupling hole and the coupling shaft; providing two full-opening stopper surfaces provided on at least two neighboring joint members to move the nozzle vanes towards the opening direction and stop the nozzle vanes at the full-opening position by contacting the two neighboring joint members to each other, the full-opening stopper position being defined by the angle between the full-opening stopper surface and the engagement line of coupling, the coupling hole and coupling shaft when the nozzle vane is positioned at the full-opening, and the distance between the full-opening stopper surface and the shaft center of the nozzle shaft when the nozzle vane is positioned at the full-opening; and providing the nozzle angle regulator with a closing stopper surface provided on the joint member and the nozzle mount respectively, the closing stopper surfaces to contact each other at the minimum opening angle position of the nozzle vanes, in which the nozzle vanes stop at the minimum opening angle position, the closing stopper surfaces being defined by the angle between the closing stopper surface and the engagement line of coupling the coupling hole and coupling shaft when the nozzle vane is positioned at the perfect closing, and the distance between the perfect closing stopper surface and the shaft center of the nozzle shaft when the nozzle vane is positioned at the perfect closing.
According to the invention mentioned above, the various effects are obtained as follows. By merely contacting the two full-opening stopper surfaces provided on the two assembled neighboring joint members (lever plates) respectively, the full-opening position of the nozzle vanes 2 can be provided easily without any additional full-opening regulating means, so the full-opening position for the nozzle vanes is easily set up. It is also possible to set up the minimum opening angle of the nozzle vanes merely by contacting the closing stopper surface 24 of the lever plate 1 to the stopper surface of the nozzle mount (nozzle mount stopper surface). These arrangements will simplify the assembling and adjustment works of the adjustable nozzle mechanism, and reduce the work account and cost for the adjustable nozzle mechanism.
In addition to the above, because each joint member (lever plate) is provided with the functions of regulating the full-opening position and the perfect closing position, no dedicated parts for regulating the full-opening position and the perfect closing position is required. It can also simplify the configuration, furthermore, it can reduce the category number of the parts and the parts number resulting in reducing the parts cost.
Furthermore, according to this invention, by providing the at least two full-opening stopper surfaces on the neighboring joint members (lever plates), which move toward the opening direction of the nozzle vanes, and stop the nozzle vanes at the full-opening position, the lever plates will create the flat contact at the full-opening stopper surfaces when the joint members are in the assembled phase. With this arrangement, it can avoid the accident of causing the turbine wheel to be damaged because the rear edges of the nozzle vanes contact to the turbine wheel due to the wearing out or cracking down of the full-opening position setting dedicated members such as a stopper pin or a long slot as mentioned earlier in the prior art.
Still furthermore, when the nozzle shaft for the nozzle vane assembles the fixed joint member (lever plate), the event in which each lever plate opens at the exceeding angle which is more than the full-opening angle, and it makes the assembling of the driving member (link plate) impossible, can be avoided. According to this invention, each joint member does not rotate more than the angle for the full-opening position by contacting the full-opening stopper surfaces of each other. This ensures the easy assembling of the nozzle driving member (link plate) and reduces the work counts for the assembling and adjusting the mechanism.